16 for (y = 0; y < 9; y++)
17 for (x = 0; x < 9; x++)
27 static int check_validity(const int col, const int row)
29 if (col < 0 || col >= 9) {
30 DPRINT << "Invalid column: " << col << std::endl;
34 if (row < 0 || row >= 9) {
35 DPRINT << "Invalid row: " << row << std::endl;
41 char sudoku::get(const int col, const int row)
43 if (!check_validity(row, col)) {
44 DPRINT << "over here\n";
48 return table[col][row];
51 int sudoku::set(const int col, const int row, const char val)
55 if (!check_validity(col, row)) {
56 DPRINT << "over here\n";
60 if (table[col][row] != EMPTY) {
61 DPRINT << "Assigning value to a non-empty slot\n";
65 str = get_col_contents(col);
66 if (str.find(val, 0) != std::string::npos) {
67 DPRINT << "Illegal assignment " << col << "." << row << ": "
72 str = get_row_contents(row);
73 if (str.find(val, 0) != std::string::npos) {
74 DPRINT << "Illegal assignment " << col << "." << row << ": "
79 str = get_block_contents(col, row);
80 if (str.find(val, 0) != std::string::npos) {
81 DPRINT << "Illegal assignment " << col << "." << row << ": "
87 table[col][row] = val;
92 int sudoku::str_to_row(const int row, const std::string &str)
94 unsigned int i, col = 0;
97 if (row < 0 || row >= 9) {
98 DPRINT << "Illegal row " << row << std::endl;
102 for (i = 0; i < str.length(); i++) {
112 /* Ignore non-numbers */
113 if (chr < '1' || chr > '9')
116 set(col++, row, chr);
123 void sudoku::print(void)
127 printf("+-------+------+--------+\n");
128 for (y = 0; y < 9; y++) {
130 for (x = 0; x < 9; x++) {
131 printf("%c ", table[x][y]);
137 printf("+-------+-------+-------+\n");
141 void sudoku::clone_to(sudoku &to)
146 for (x = 0; x < 9; x++)
147 for (y = 0; y < 9; y++)
148 to.table[x][y] = table[x][y];
151 std::string sudoku::get_row_contents(int row)
156 for (col = 0; col < 9; col++) {
157 if (table[col][row] != EMPTY)
158 s += table[col][row];
164 std::string sudoku::get_col_contents(int col)
169 for (row = 0; row < 9; row++) {
170 if (table[col][row] != EMPTY)
171 s += table[col][row];
177 std::string sudoku::get_block_contents(int col, int row)
183 if (col < 0 || col >= 9)
184 DPRINT "Aiee " << col << std::endl;
185 if (row < 0 || row >= 9)
186 DPRINT "Aiee " << row << std::endl;
188 col = (col /= 3) * 3;
189 row = (row /= 3) * 3;
191 for (y = 0; y < 3; y++)
192 for (x = 0; x < 3; x++) {
193 c = get(x + col, y + row);
203 static std::string exclude_common(std::string s1, std::string s2)
205 std::string::iterator a, b;
208 for (a = s1.begin(); a != s1.end(); a++) {
209 for (b = s2.begin(); b != s2.end(); b++) {
220 std::string sudoku::get_legal_numbers(int col, int row)
223 std::string a, b, c, ret;
225 if (!check_validity(col, row)) {
226 DPRINT << "over here\n";
235 // std::cout << "[" << col << "." << row << "] ";
237 a = get_col_contents(col);
238 // std::cout << " col " << a;
240 b = get_row_contents(row);
241 // std::cout << " row " << b;
243 c = get_block_contents(col, row);
244 // std::cout << " block " << c;
246 ret = exclude_common("123456789", a);
247 ret = exclude_common(ret, b);
248 ret = exclude_common(ret, c);
250 // std::cout << " legal " << ret << std::endl;
254 int sudoku::fill_missing()
256 int x, y, solved = 0;
259 for (y = 0; y < 9; y++)
260 for (x = 0; x < 9; x++) {
261 num = get_legal_numbers(x, y);
262 if ((num != "0") && (num.length() == 1)) {
268 std::cout << "Solved " << solved << " numbers\n";
274 int sudoku::get_best_guess(int &col, int &row)
277 int min = 0, filled = 0, illegals = 0;
281 * Initialize row and col with illegal values to spot possible
287 for (y = 0; (y < 9) && !illegals; y++)
288 for (x = 0; x < 9; x++) {
289 numbers = get_legal_numbers(x, y);
291 if (numbers == "0") {
296 if (numbers.length() == 0) {
302 min = numbers.length();
308 if ((int)numbers.length() < min) {
309 min = numbers.length();
315 // std::cout << x << "." << y << ": " << " min "
316 // << numbers << col << "." << row << std::endl;
319 if ((!min && !filled) || illegals) {
320 // DPRINT << "Is this sudoku has no solutions?\n";
324 if (!min && (filled == 99)) {
325 DPRINT << "This sudoku is solved\n";
332 sudoku sudoku::solve(int &solvable)
338 // Fill in as much as possible
341 std::cout << std::endl;
344 } while (fill_missing() != 0);
346 ret = get_best_guess(x, y);
348 // Did we solve it yet?
354 std::cout << "This is unsolvable, recursion: "
355 << recursion_depth << std::endl;
362 std::cout << "Solution found , recursion: "
363 << recursion_depth << std::endl;
369 std::cout << "Not solved yet, guessing at depth "
370 << recursion_depth << std::endl;
373 // Try guessim something
374 str = get_legal_numbers(x, y);
375 for (i = 0; i < (int)str.length(); i++) {
377 sudoku guess = *this;
378 guess.set(x, y, str[i]);
381 std::cout << "Guessing number " << str[i] << " to "
382 << x << "." << y << std::endl;
385 guess.recursion_depth = recursion_depth + 1;
388 guess = guess.solve(can_solve);
400 std::vector<sudoku> sudoku::solve_all()
404 std::vector<sudoku> sudokus;
406 // Fill in as much as possible
409 std::cout << std::endl;
412 } while (fill_missing() != 0);
414 ret = get_best_guess(x, y);
416 // Did we solve it yet?
421 std::cout << "This is unsolvable, recursion: "
422 << recursion_depth << std::endl;
428 std::cout << "Solution found , recursion: "
429 << recursion_depth << std::endl;
431 sudokus.push_back(*this);
437 std::cout << "Not solved yet, guessing at depth "
438 << recursion_depth << std::endl;
441 // Try guessim something
442 str = get_legal_numbers(x, y);
443 for (i = 0; i < (int)str.length(); i++) {
444 std::vector<sudoku> results;
446 sudoku guess = *this;
450 std::cout << "Guessing number " << str[i] << " to "
451 << x << "." << y << std::endl;
454 guess.set(x, y, str[i]);
455 guess.recursion_depth = recursion_depth + 1;
457 results = guess.solve_all();
460 if (!results.empty()) {
461 /* printf("Got %d solutions, guessed %d: %s\n",
462 (int)results.size(), (int)str.size(),
465 for(j = 0;j < (int)results.size(); j++)
466 sudokus.push_back(results.at(j));
470 // Return what was solved